Write unit test cases for all functions

[Chrahuldeveloper]

Add comprehensive unit tests for all functions to ensure reliability and maintainability.
The tests should mock the node-appwrite SDK to avoid real API calls and verify that each function:

• Calls the correct Appwrite methods with expected parameters.
• Returns the correct values on success.
• Handles and propagates errors properly.

Use Jest for testing, and include both positive and negative scenarios for full coverage.

[Chrahuldeveloper]

@M4dhav Hey bro i would love to work on this